The initial source of energy is Sun. The frog depends on the insects and hence, it does not directly receives energy from the initial source. The moth are related to butterflies and they also does not receives energy from the sun. Shrew are small moles and they eat other small insects like grasshopper, hence they also does not directly receives energy from the sun.
Trees uses sunlight for photosynthesis to produce food. Hence, they receive energy directly from the initial source.